A filter may be implemented at the physical layer (also termed layer 1) or a network layer (also termed Layer 3) of a logically layered architecture of a wireless communication device. A filter at the layer 3, L3 for short, in general is more flexible for modification and adjustment. Layer 3 is a logical layer and may be responsible for communications with peer network entities, control of network signaling and user data flow. For example, L3 may be responsible for the control of packet forwarding including routing through intermediate routers, whereas the data link layer, part of the layer 2, is responsible for media access control, flow control and error checking.
In telecommunication systems, measured quantities of signal strength are typically filtered using a network defined coefficient value. In a UMTS network, typically the signal quantities of cells (e.g., RSCP and ECNO) are filtered using a running Infinite Impulse Response (IIR) filter with a coefficient defined by the network. The use of a network determined coefficient value may lead to a situation where the filtered quantities are either too slow to react to fast changing signal levels or are unable to filter out the unwanted high frequency components that may cause erroneous event triggering.
Another case is a heterogeneous network (HetNet), where an adjustable L3 filter may be desirable. In a HetNet scenario, a user equipment (UE) may need to make decisions on parameter adjustment autonomously, with limited or minimal control signaling from the associated network. A UE with the capability to just performance related parameter such as L3 filter coefficient may be very beneficial.
Following abbreviations are used in this application.    BS Base Station    CPICH Common Pilot Channel    DPCCH Dedicated Physical Control Channel    E-DCH Enhanced Data Channel    ECNO Received Energy Per Chip/Power density in Band    EUTRAN Enhanced UTRAN    HetNet Heterogeneous Network    HS-DPCCH High Speed-Dedicated Physical Control Channel    IIR Infinite Impulse Response    LTE Long Term Evolution    MAC Medium Access Control    RSCP Received Signal Code Power    UE User Equipment    UMTS Universal Mobile Telecommunications System    UTRAN UMTS Radio Access Network    WCDMA Wideband Code Division Multiple Access